JPS6236612A - Optical coupler - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is applicable to two types of semiconductor lasers, lenses, etc.
The present invention relates to an optical coupling device that connects two optical elements to each other while maintaining optical coupling between the respective bases.

[Prior art] In general, in optical fiber transmission systems, efficient optical transmission can be achieved by aligning the light source, lens, optical fiber, etc. with each other with high precision and holding them securely. becomes.

Optical coupling 5a using a semiconductor laser (LD) as the light source and a single mode optical fiber (SMF) as the optical fiber
Various lens systems for lt (LD module) are shown in Figure 10~
It is shown in FIG. Figure 10 shows a confocal compound lens system (Saruwatari et al.
um E Iectron vol, Q E
-17,1) 11.1021-1027. June 1
981), and the beam emitted from LDlol is converted into approximately parallel light by the second lens 105, and the second
The light enters the SMF 107 via the lens 105.

In this case, since the SMF 107 is separate from the second lens 105, the tolerance for the axis deviation of the SMF 107 is strict. That is, the second lens 10
5 and the SMF 107 becomes difficult.

On the other hand, in the second lens split type confocal compound lens system shown in FIG.
The structure is such that the beam is incident on the 12th
Pseudo confocal compound lens system (All) shown in the figure 1. Opt
, vou, 24. l) L 984-989. Ap
r, 1985) has a configuration in which a beam that is slightly narrower than the second lens 109 is incident on the second lens 111 that is integrated with the SMF 107, and both of them are SMF 10.
SMF10 is better than the lens system shown in Figure 10 where 7 is a single unit.
The tolerance for axis misalignment of No. 7 is relaxed.

However, in the above three lens systems, the lens 103 (
The tolerance for axis misalignment of 113) is the microlens system (Saruwatari et al., AI) I) Q, Opt, you, 18, positive 11. pp, 1847-1856. June.

1979), the SMF of the LD module is very severe.
The output of 107 is degraded by several dB.

Therefore, in order to realize an L'D module that maintains a high level of safety and reliability, it is essential to have a technology that suppresses the axis deviation, especially in the direction perpendicular to the optical axis of the first lens 103 (113), after the LD module is assembled. Becomes absentee.

By the way, the second lens 109 (113) of the LD module
), generally, as shown in FIGS. 13 and 14, after fixing the lune 103 (113) to its holder 115 with adhesive, solder, or low melting point glass, the holder 115 is attached to the LD. It is fixed to the stem 117 with adhesive or solder. However, when adhesive is used, axis misalignment tends to occur between the holder 115 and the LD stem 117.
Furthermore, it takes a long time for the adhesive to solidify, resulting in poor workability, and there are also problems such as the LD being deteriorated by the gas generated from the adhesive.

For this reason, solder, which is a non-resin bonding agent, is generally used to fix the holder and the LD stem. Figures 15 and 16 show the joining method of A.
After fitting the ring-shaped solder 119 to the lower end of the holder 115, the boulder 115 is brought to the optimum position while observing the LD beam emitted from the lunes 103 or monitoring the SMF output, and is heated by a high-frequency induction heating device. Solder 119 is melted and fixed. (See FIGS. 17 and 18.) In FIGS. 13 to 18, reference numeral 121 is the LD, and reference numeral 123 is the driving electrode of the LD 121. ) [Problems to be Solved by the Invention] However, in such conventional bonding between the holder and the LD stem, it is difficult for solder to flow between the holder and the LD stem, resulting in weak adhesion and creep after soldering. Current Mongolia (Mitomi et al. proc, IEEECHMT Symp
, , (Tokyo), ppl 98-204
．． 1984), which tends to cause axial misalignment of the holder, resulting in a problem in that the reliability of the ILD module is significantly impaired.

This invention was devised by focusing on these conventional problems, and aims to provide sufficient strength to the bond between two optical elements such as a semiconductor laser or a lens to prevent axis misalignment between each element. The purpose is to provide an optical coupling device.

[Means for solving the problem] In order to achieve this object, the present invention includes a first base that holds a first optical element, a second base that holds a second optical element, and a second base that holds a second optical element. the first base and the second base so that the first optical element and the second optical element are optically coupled to each other.
In the optical coupling device, a plurality of notches are provided in the joint portion of at least one of the two bases in the optical coupling device in which the two bases are fixed to each other by a joining means.

[Example] Hereinafter, the present invention will be described in detail based on the drawings. 1 to 5 show a first embodiment of the invention. 1st
A semiconductor radar (hereinafter referred to as LD) stem 1, which serves as a base for
A D-integrated portion 1b is formed. An LD3 as a first optical element is incorporated and held in the upper center side of the LD incorporating part 1b, and the driving electrode 5 of this LD3 is connected to the LD.
It penetrates the base 1a from the side '17 ('J) of 3 and protrudes to the outside.

The lens holder 7 has a lens accommodating hole 7a formed in its center, and a ``''-shaped lens 9 that receives the beam emitted from the LD 3 is fixed in the lens accommodating hole 7a with adhesive or the like. Further, a cylindrical portion 7b is formed on the lower surface of the outer peripheral end of the lens holder, and a plurality of rectangular notches 11 are formed on the lower end of the cylindrical portion 7b, so that the LD mounting portion 1b of the LD stem 1 is formed.
The lens holder 7 will cover this.

In this way, the lens holder 7 and the LD stem 1 are joined together by applying solder (not shown) as a ring-shaped joining means to the lower end of the cylindrical part 7b of the lens holder 1, as shown in FIGS. 15 and 16 described in the prior art section. The solder is then melted using a high-frequency heating device. As shown in FIGS. 3 and 4, since the molten solder 13 enters the notch 11, the wetted area of the solder becomes wider than in the past, and the bonding between the lens holder 7 and the LD stem 1 is significantly reduced. improves. Furthermore, the monitorability of solder wetting is also excellent.

FIG. 5 shows the heat cycle (
-10 to 60°C, 4 hours/1 cycle) is an example of a test (the solid line is this example, the broken line is the conventional example). As is clear from this, by using the lens holder according to the embodiment of the present invention, stability is significantly improved compared to using a lens holder having a conventional structure.

In addition, as a result of actually manufacturing the DT-Joule in this way, we found that lens holders 7 and L have the tightest tolerance for axis misalignment.
The ability to monitor solder wetting with the D stem 1 is improved, and it becomes easier to determine whether the LD module is good or bad.

6 and 7 show a second embodiment. In this embodiment, the lower end of the cylindrical portion 7b of the lens holder is expanded outward to form a flange-like portion, and a rectangular notch 11 is provided in the flange-like portion. The joining method is similar to the above-described embodiment, in which a ring-shaped half F0 (not shown) is fitted into the lower end of the cylindrical portion 7b and melted using a high-frequency induction heating device. As a result, the melted solder enters the notch 11 as in the previous embodiment, so that the lens holder 7 is firmly joined to the D stem 1.

FIGS. 8 and 9 show a third embodiment. In this embodiment, no cutout is provided on the lens holder side, and L
A notch 11 is provided on the D stem 1 side. This notch 11 is formed on an annular protrusion 15 that has an inner diameter larger than the outer diameter of the cylindrical portion 7b of the lens holder 7 and is formed on the upper surface of the base 1a of the LD stem 1 on the outer side of the LD mounting portion 1b. I'm letting you do it. However, the cylindrical portion 7b of the lens holder 7 is
This annular protrusion 15 and the LD assembly portion 1b of the LD stem 1
It will be inserted between. In this case, a ring-shaped solder (not shown) is fitted onto the outer periphery of the lens holder so as to contact the upper end of the annular projection 15. In this state IyJ
As in each of the above-mentioned embodiments, solder is melted to join the lens holder 7 to the D stem 1, and the melted solder is applied to the notch 1.
1, this bond also becomes strong.

Note that the present invention is not limited to each of the above-described embodiments. For example, instead of using a spherical lens to receive the beam from the LD, a converging Ronde lens or a spherical lens with a tip GR,
An IN rod lens or the like may be used, and the lens holder is not limited to a cylindrical shape, but may also be a prismatic shape. Also,
To avoid melting the solder, a burner, laser, etc. may be used. Furthermore, the same effect can be obtained by using a plurality of spherical solders instead of ring-shaped solders. Note that when spherical solder is used, workability will be improved if a hole or groove is provided for placing the solder.

[Effects of the Invention] As described above, according to the present invention, there is a notch in the joint portion of at least one of the first base holding the first optical element and the second base holding the second optical element. Since the two bases are joined by the joining means, the joining means can easily enter between the two bases, and as a result, the joining force between the two bases is strong, and the distance between each optical element is increased. axis misalignment can be prevented.

[Brief explanation of the drawing]

1 to 5 relate to the first embodiment of the present invention, in which FIG. 1 is a perspective view of the LD module covered with a lens holder, FIG. 2 is a sectional view thereof, and FIGS. Figure 4 is L
A perspective view and a cross-sectional view showing the state in which the D module and the lens holder are joined; FIG. 5 is a dimensional explanatory diagram showing the heat cycle test results of the LD module for SMF according to the conventional example and the first embodiment; FIG. and FIG. 7 are a perspective view and a sectional view corresponding to FIGS. 1 and 2 of the second embodiment, respectively, FIGS. 8 and 9 are a perspective view and a sectional view of the third embodiment, respectively, Figures 10 to 12 are schematic configuration diagrams showing various lens systems of 10 modules for SMF, and Figures 13 to 12
FIG. 18 relates to a conventional example, FIGS. 13 and 14 are perspective views and top views corresponding to FIGS. 17 and 18 are perspective views and sectional views corresponding to FIGS. 3 and 4, respectively. 1... LD stem (first base) 3... LD (first optical element) 7... Lens holder (second base) 9... Lens (second optical element) 11... Notch 13... Solder (joining means) Fig. 1 Fig. 2 Fig. 8 Fig. 4 Fig. 5 Heat cycle & (-1 series modification, 4 cycles/cycle)
Figure 6 Figure 7 Figure 8 Figure 9 Figure 10 Figure 11 Figure 12 Figure 13 Figure 14 Figure 15 Figure 16

Claims (1)

[Claims] It has a first base that holds a first optical element and a second base that holds a second optical element, and the first optical element and the second optical element are optically connected to each other. In the optical coupling device for fixing the first base and the second base to each other by a joining means, a plurality of cutouts are provided in the joint of at least one of the two bases. An optical coupling device characterized by: